Help with Table and Row indexing

Hi,

I have the following table Predictions, where there are 2 Days, 2 different Time points, for 2 different Birds, 3 Tries per day.

I want to:

1. Check If the Row number is a True Positive (meaning the column True and Predicted have the same value)
2. Check If the Row number is a True Positive and the Predicted value is '1'. Save those Row numbers in a variable called RN.
3. From another table T with the same dimentions as the Predictions table, I only want to keep the Row numbers as assigned to RN.

Can you help?

Answer 1

[Voss]

S = load('predictions.mat');
Predictions = S.Predictions

Predictions = 22×6 table
    Day    Bird    Time    Try    True    Predicted
    ___    ____    ____    ___    ____    _________

     1     004     Pre      1      0          0    
     1     004     Pre      2      0          0    
     1     004     Pre      3      0          0    
     1     004     Post     1      0          0    
     1     004     Post     2      0          0    
     1     004     Post     3      0          0    
     1     006     Pre      1      1          1    
     1     006     Pre      2      1          1    
     1     006     Pre      3      1          1    
     1     006     Post     1      1          1    
     1     006     Post     2      1          1    
     2     004     Pre      1      0          0    
     2     004     Pre      2      0          0    
     2     004     Pre      3      1          0    
     2     004     Post     1      0          0    
     2     004     Post     2      0          0    

isTruePositive = Predictions{:,'True'} == Predictions{:,'Predicted'};

isTruePositivePredicted1 = isTruePositive & Predictions{:,'Predicted'} == 1;

% here are the row numbers:
RN = find(isTruePositivePredicted1)

RN = 8×1

7 8 9 10 11 18 19 21

% Two different ways to keep only certain rows 
% of the other table T:

% Option 1: use logical indexing, and discard 
% rows of T that are not true positive where 
% 1 was predicted (in this case you don't need RN):
T{~isTruePositivePredicted1,:} = [];

% Option 2: use row indices RN to keep those rows 
% that are true positive where 1 was predicted:
T = T{RN,:};